1

Jabatan Kejuruteraan Elektrik

Politeknik Port Dickson

Address: KM14,Jalan Pantai

71050 SiRusa,

Negeri Sembilan

No. Tel: 06-6622000

No. Fax: 06-6622025

www.polipd.edu.my

First Edition

All rights reserved.

No part of this publication may be reproduced, stored in a retrieval

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mechanical, photocopying, recording or otherwise, without prior

permission of Politeknik Port Dickson(PPD).

Published by:

Politeknik Port Dickson

Address: KM14,Jalan Pantai

71050 SiRusa,

Negeri Sembilan

ISBN

ACKNOWLEDGEMENTS

Satellite technology is developing fast, and the applications

for satellite technology are growing very rapidly and increasing all

the time. Satellites can be used for many type of applications, not

only in radio communications, but many more. All the information of

this book are gathered from the references book listed. The author

took the initiative to compile all the information and produce this

e-book as a reference for polytechnic student and other as a

guidance and references.

Alizawati binti Mat Zim

Port Dickson

June 2020

CONTENT

Introduction To Satellite Communication 2

1.1 Structure Of Satellite 4

1.2 Satellite Orbit 6

1.3 Frequency Allocations For Satellite Communication System 7

1.4 Satellite Orbital 12

1.5 Look Angles Of Satellite 18

1.6 Earth Coverage Area (Foot Print) 22

1.7 Orbit Inclination And Latitude Coverage 26

Satellite System Elements 28

2.1 Satellite System 29

2.2 Space Segment 31

2.3 Earth Segment 40

2.4 Satellite Organizations 46

2.5 Satellite Services 48

Satellite Communication System 57

3.1 Multiple Access Methods 58

3.2 Frequency Division Multiple Access 60

3.3 Time Division Multiple Access 63

3.4 Code Division Multiple Access 66

3.5 Satellite System Links 69

3.6 Satellite Link Budget. 71

3.7Very Small ApertureTerminal Network 79

1

Topic1

INTRODUCTION TO

SATELLITE

COMMUNICATION

What is Satellite?

» Satellite is a physical object that moves

around the earth.

» It occurs either naturally or man-made

» The moon orbiting the Earth

» The man-made satellites orbit earth

Satellites are used for a large number of purposes. Common types

include military and civilian Earth observation satellites,

communications satellites, navigation satellites, weather satellites, and

research satellites. Space stations and human spacecraft in orbit are

also satellites. Satellite orbits vary greatly, depending on the purpose

of the satellite, and are classified in a number of ways. Well-known

(overlapping) classes include low Earth orbit, polar orbit, and

geostationary orbit.

2

sun

earth

moon

INTRODUCTION TO SATELLITE

COMMUNICATION

• In general satellite is an artificial satellite stationed in space for

the purposes of telecommunications, military, surveillance, ect

• A communications satellite is an orbiting artificial earth satellite

that receives a communications signal from a transmitting ground

station, amplifies and possibly processes it, then transmits it back

to the earth for reception by one or more receiving ground

stations.

• The satellite is an active transmission relay, similar in function to

relay towers used in terrestrial microwave communications.

• It contains several transponders which listens to some portion of

the spectrum, amplifies the incoming signal and broadcasts it in

another frequency to avoid interface with incoming signals.

• Satellite technology is developing fast, and the applications for

satellite technology are increasing all the time. Not only can

satellites be used for radio communications, but they are also

used for astronomy, weather forecasting, broadcasting, mapping

and many more applications.

3

4

Structure of satellite

• Satellites come in many shapes and sizes. But most have at least

two parts in common an antenna and a power source.

• The antenna sends and receives information, often to and from

Earth. The power source can be a solar panel or battery. Solar

panels make power by turning sunlight into electricity.

• Many NASA satellites carry cameras and scientific sensors.

Sometimes these instruments point toward Earth to gather

information about its land, air and water.

• Most satellites are launched into space on rockets.

5

Structure of satellite

The path followed by a satellite

is called an orbit

The orbit’s plane always passes through the center of the Earth

Types of Orbital shape

Circular orbit

The distance from the Earth remains the same at all times.

Elliptical orbit

The elliptical orbit changes the distance to the Earth

6

Satellite Orbit

7

Frequency Allocations For Satellite Communication

System

Satellite Frequency Band

With the variety of satellite frequency bands that can be used,

designations have been developed so that they can be referred to

easily.

The higher frequency bands typically give access to wider bandwidths,

but are also more susceptible to signal degradation due to ‘rain fade’

(the absorption of radio signals by atmospheric rain, snow or ice).

Because of satellites’ increased use, number and size, congestion has

become a serious issue in the lower frequency bands. New

technologies are being investigated so that higher bands can be used.

L-band (1–2 GHz)

Global Positioning System (GPS) carriers and also satellite mobile

phones, such as Iridium; Inmarsat providing communications at sea,

land and air; WorldSpace satellite radio.

S-band (2–4 GHz)

Weather radar, surface ship radar, and some communications

satellites, especially those of NASA for communication with ISS and

Space Shuttle. In May 2009, Inmarsat and Solaris mobile (a joint

venture between Eutelsat and Astra) were awarded each a 2×15

MHz portion of the S-band by the European Commission.

C-band (4–8 GHz)

Primarily used for satellite communications, for full-time satellite TV

networks or raw satellite feeds. Commonly used in areas that are

subject to tropical rainfall, since it is less susceptible to rainfade than

Ku band (the original Telstar satellite had a transponder operating in

this band, used to relay the first live transatlantic TV signal in 1962).

8

9

Ku-band (12–18 GHz)

Used for satellite communications. In Europe, Ku-band downlink is

used from 10.7 GHz to 12.75 GHz for direct broadcast satellite

services, such as Astra.

Ka-band (26–40 GHz)

Communications satellites, uplink in either the 27.5 GHz and 31

GHz bands, and high-resolution, close-range targeting radars on

military aircraft.

10

The higher the frequency, the more bandwidth is available, but the

equipment needs to be more sophisticated.

Advantage and Disadvantage (C-Band)

Advantage and Disadvantage (Ku-Band)

Advantage and Disadvantage (Ka-Band)

11

Types of Circular Orbit :

• LEO : Low Earth Orbit

• MEO : Medium Earth Orbit

• GEO : Geostationary Earth Orbit

12

Satellite Orbital

13

Low Earth Orbit (LEO)

• LEO satellites are much closer to the earth , ranging from 500

to 1,500 km above the surface.

• LEO satellites must travel very fast so gravity does not pull them

back into the atmosphere.

• Rotation period is 90 min

• Shortest life (5-8 years)

LEO satellites, with proper inclinations, can cover high latitude

locations, including polar areas, which cannot be reached by GEO

satellites. E.g. Satellite Telephones, ISS

14

Medium Earth Orbit (MEO)

• Operate at a distance of about 8,000 km and 20,000 km above

the earth’s surface.

• Rotation period 5-12 hour

• Difficult due to radiation belts

• MEO satellites have a larger coverage area than LEO satellites.

• Communications satellites that cover the North and South Pole

are also put in MEO.

• Telstar, one of the first and most famous experimental satellites,

orbits in MEO.

• E.g: Meteorological satellite, GPS

15

Geostationary Earth Orbit (GEO)

• Satellite are paled above a equator at a distance of 35863km

• 24 hour rotation

• Long life 10-15 years.

• Objects in Geostationary orbit revolve around the earth at the

same speed as the earth rotates. This means GEO satellites

remain in the same position relative to the surface of earth.

Because geostationary satellites circle the earth at the equator, they

are not able to provide coverage at the Northern and Southern

latitudes.

Geostationary orbits are ideal for weather satellites and

communications satellites.

GEO satellites move around the earth at same speed as earth mores

around the sun. This ensures constant communication and the

satellite seems to remain fixed above a certain spot.

As the orbital speed depends on the distance from the planet, only

one orbit can be geo-stationary.

Because of the curvature of the earth one geo-stationary satellite

cannot cover the whole earth. In takes a minimum of three satellites

equidistant from each other in geo-stationary earth orbit (GEO) to

provide full global transmission.

16

Advantages of geostationary satellite

• A GEO satellite’s distance from earth gives it a large coverage

area, almost a fourth of the earth’s surface.

• GEO satellites have a 24 hour view of a particular area.

• Ideal for satellite broadcast and other multipoint applications.

• The geostationary orbit is useful for communications

applications because ground based antennas, which must be

directed toward the satellite, can operate effectively without the

need for expensive equipment to track the satellite’s motion.

Disadvantages of geostationary satellite

• A GEO satellite’s distance also cause it to have both a

comparatively weak signal and a time delay in the signal, which is

bad for point to point communication.

• GEO satellites, centered above the equator, have difficulty

broadcasting signals to near polar regions

• require sophisticated and heavy propulsion devices on board to

keep them in a fixed orbit

Parameter LEO MEO GEO

Satellite Height 500 – 1500 km2000 – 30000

km35 800 km

Orbital Period 90 min 5 – 12 hours 24 hours

Number of

Satellites40 – 80 8 - 20 3

Satellite Life Short Long Long

Number of

HandoffsHigh Low

Least

(none)

Propagation

LossLeast High Highest

17

Differences between LEO, MEO, GEO

Satellite height: For many orbit calculations it is necessary to

consider the height of the satellite above the geocentre. This is the

height above the Earth plus the radius of the Earth. This is generally

taken to be 3960 miles or 6370 km.

Look Angle: the coordinates to which earth station(ES) must point

to communicate with a satellite.These are:

• Azimuth angle (AZ)

• Elevation angle (EL)

Generally, the values of these angles change for non-geostationary

orbits. Whereas, the values of these angles don’t change for

geostationary orbits. Because, the satellites present in geostationary

orbits appear stationary with respect to earth.

These two angles are helpful in order to point at the satellite

directly from the earth station antenna. So, the maximum gain of the

earth station antenna can be directed at satellite.

We can calculate the look angles of geostationary orbit by using

longitude & latitude of earth station and position of satellite orbit.

18

Look Angles Of Satellite

19

Azimuth Angle

Azimuth is defined as the angle between local horizontal plane and

the plane passing through earth station, satellite and center of earth.

The horizontal pointing angle of an antenna (0° – 360°). It refers to

the rotation of the whole antenna around a vertical axis. It is the

side to side angle.

It is measured in a clockwise direction in degrees from true north

(north pole 0°) which is used as reference.

Elevation Angle

The angle of elevation is the angle between the horizontal plane

and the pointing direction of the antenna.

The smaller the angle of elevation, the greater the distance a

propagated wave must pass through the earth's atmosphere.

20

21

Azimuth & Elevation Angle

22

Earth Coverage Area (Foot Print)

Satellite Altitude and Earth Coverage Area

• Earth coverage also known as footprint, is the surface area of

the earth that can possibly be covered by a given satellite.

• The effect of satellite altitude on earth coverage provided by the

satellite.

• The coverage area increases with the height of the satellite

above the surface of the earth.

• It varies from 1.5% of the earths surface area for a low earth

satellite orbit at 200km to about 43% of the earth surface area

for a satellite at a geostationary height of 36000km.

The increase in coverage area with an increase in altitude is steeper

in the beginning than it is as the altitude increase beyond 10000km.

The higher the altitude of the satellite, the smaller is the angular

velocity and the greater will be the displacement of the ground

track towards the west due to the earth rotation.

23

Satellite Antenna Radiation Patterns: Footprints

Satellite orbits Period and Footprints

24

Footprint Categories

• Spot – for small geographic are

• Zonal –covers approximately a continent

• Hemispherical – which covers about half of the visible earth

• Earth(Global) – earth coverage of the visible earth.

25

Spot and Zonal Beams:

• Concentrated power to very small geographical areas

• Have high EIRPs

• Blanket less than 10% of earth’s surface

Hemispherical Beam

• Blanket 20% of Earth’s surface

• Have EIRP that are 3dB lower than spot beams

Earth(Global)

• Beam width of approximately 17˚

• Coverage of up to 42% of earth’s surface

• Power levels are considerably low

• Require large receive dishes for adequate signal detection

** Effective isotropic radiated power (EIRP) is defined as an equivalent

transmit power

• The north and south latitudes of the terrestrial segment covered

by the satellites ground track depend on the satellite orbit

inclination.

• The zone from the extreme north latitude to the extreme

southern latitude, which is symmetrical about the equator, is

called the latitude coverage.

• Figure below illustrate the extent of latitude coverage for

different inclination.

• It can be seen that the latitude coverage is 100% only in the case

of polar orbits. The higher the orbit inclination, the greater is the

latitude coverage.

26

Orbit Inclination and Latitude Coverage

27

Angle of Inclination

• This figure show the angle of inclination between the equatorial

plane and the orbital plane.

• A satellite orbiting in any plane not identical with the equatorial

plane is in an INCLINED ORBIT.

• The inclination of the orbit determines the area covered by the

path of the satellite.

• The greater of inclination, the greater amount of surface area

covered by the satellite.

91

REFERENCES

1. Anil K. Maini, Varsha Agrawal, Satellite Technology: Principles and Applications

2. Satellite Times, Geostationary Orbits, Dr. T.S. Kelso, 1998

3. Satellite Communication System Engineering, Louis J. Ippolito, 2008, John Willey

& Son Ltd, (ebook)

4. EE 526, Satellite Communication, Farid Bouges Bandar Saman, Prof. Adnan

Afandi, http://www.geocities.ws/ffbouges/ffb.htm

5. http://www.tpub.com/neets/book17/76.htm

6. http://www.gif-paradies.de/gegenstaende/satelliten.html

7. http://www.radio-electronics.com/info/satellite/satellite-orbits/satellite-

launching.php

8. Satellite Communication, 4th edition, Dennis Roddy, 2006, Mc-Graw Hill

(Ebook)

9. Fundamentals of satellite communication system,

http://vsagar.com/2011/12/10/fundamentals-of-satellite-communication-system/

10. Satellite Communications,

http://share.pdfonline.com/8a5f48fc99564b94bd0bbfaa3281373d/Satellite%20Co

mm-LecIII.htm

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https://www.courses.psu.edu/aersp/aersp055_r81/satellites/satellites.html

12. Satellite Technology: Principles and Applications, By Anil K. Maini, Varsha

Agrawal

13. Satellite Link Design: A Tutorial, Aderemi A. Atayero, Matthew K. Luka and

Adeyemi A. Alatishe, http://www.ijens.org/vol_11_i_04/110904-3232-ijecs-

ijens.pdf

14. Satellite Communications for the Non specialist, Mark R. Chartrand,

http://books.google.com.my

15. Satellite Data Networks, Rizwan Mustafa Mir,

http://www.cse.wustl.edu/~jain/cis788-97/ftp/satellite_data/index.htm

16. JSAT international, http://www.jsati.com/why-satellite-what-Power.asp

17. Marine Satellite Systems,

http://www.marinesatellitesystems.com/index.php?page_id=98

18. Satellite advantages http://www.slideshare.net/arattupuzha/satelite-

communication

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http://www.rfcafe.com/references/articles/Satellite%20Comm%20Lectures/Satellit

e-Comms-Link-Budget.pdf

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http://www.electronica.udea.edu.co/cursos/sistemasc/LINK%20BUDGET.ppt

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